simpson - crackingtheconcreteanchorcodes

8/20/2019 Simpson - CrackingtheConcreteAnchorCodes

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Agenda

Introductions

Overview of Anchor Codes

Detailed Look at ACI318 Appendix D

Detailed Look at ICC-ES Acceptance Criteria

Software Demonstration

Summary


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Simpson Strong-Tie 101

We re separate from the WOOD Division

Anchor Systems Pursues Opportunities Beyondthe Wood Industry

:

:

TECHNICAL MANUAL

Anchoring & Fastening Systems for

Concrete & Masonry

ADHESIVES

MECHANICAL ANCHORS

POWDER ACTUATED FASTENENING

CARBIDE BITS & CHISELS

Anchor Systems Binder


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Core Product Lines

AdhesivesAnchoring

Crack repair

Mechanical Anchors

Powder Actuated

Carbide Bits

Acrylic-Tie SET Epoxy ETI-LV

Strong-BoltTiten HD

Educating you:

Industry & Code changes

Product developments

Review your Notes/Specs forcode compliance

Technical Support

Provide Field Support:

Onsite Anchor Training

Initial Anchor InstallationObservation

Specify Simpson Anchors:

Details

General Notes

Specification Sections

Project Leads


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Overview of ConcreteAnchor Code Provisions

Topics to be covered

Anchor Design Methods (past & present)Building Codes

International Building Code (IBC)

Material CodesACI318 Appendix D

ACI355.2

Evaluation Entities

ICC-ES

Acceptance Criteria

Research Reports (aka Code Reports)

What Anchor Products Can Be Used?


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Why is All This Important?The Devil is in the Details

History of Anchor Design

(before & after 2003)


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Prior to 2003

All code provisions for anchors were only for cast-in-place anchor typesUBC97

IBC2000

PCI

ACI349-01

AISC Steel Manual

Permitted both ASD and USD Design MethodsASD = Allowable Stress Design

USD = Ultimate Strength Design

CIP Anchor Design Methods

Allowable Stress Design Tables

UBC97

IBC2000

Valid for ONLY headed bolts (and only if non-seismic applications)


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CIP Anchor Design Methods

Ultimate Strength Design Method

( the 45o cone method)

UBC97

PCI (< 5th Edition)

ACI 349-01

IBC2000 (35o CCD Method)

None of These ProvisionsAddressed Post-Installed Anchors


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Post-Installed Anchor Design

Post-installed anchors were typically considered Alternate Materials

ICC

Research Reports

ICC-ES is the leading Code Report-writing entity

ICC-ES establish Acceptance Criteria (AC) forproducts NOT prescribed by code

AC s determine the minimum levels of performancefor Alternate Materials to meet code s intent

Original AC s for anchor productsAC01 expansion anchorsAC58 adhesive anchorsAC106 screw anchors

Established safety factors

Not all tests in AC were mandatorySeismicLong/short term loading (creep)Exterior exposure (freeze/thaw)

Prior to 2003, all AC s were limited to uncrackedconcrete only

As there was no established test to evaluateperformance in cracked concrete

ICC-ES

AC01, 58, 60, 70,

106, 193, 308

r e s e a r c h r e p o r t


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Evaluation Report Process:Manufactures submitindependent testing toICC-ES for their review

Evaluated against AC s

ICC-ES issues Code Reports

Reports available online:ICC-ES

www.icc-es.org

Anchor Manufacturer swebsites

www.simpsonanchors.com

Research Reports

Important Sections

1.0 Evaluation Scope

2.0 Uses

4.0 Design & Installation

Special Inspection

Anchor Capacity Tables

Research Reports

http://www.simpsonanchors.com/http://www.icc-es.org/


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Then Came Along IBC2003

Then Came Along IBC2003


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How All These Codes Relate

Building Code (IBC2003)

Tells what anchor design method to useReferences Material Code

Concrete Material Code

(ACI318 - Appendix D)

Tells how to design the anchor

References an Anchor Test Standard

Anchor Test Standard (ACI355.2)Tells how to test & evaluate the anchor

Acceptance Criteria (ICC-ES AC s)

Establishes the minimum intent of Codein order to get an Evaluation Reportshowing approval for specificapplications

Newer AC s modify Appendix D w/Design Information

International Building Code

IBC2003 Sec. 1912 (similar IBC2006 Sec. 1911)

Allowable Stress Design permitted if

Cast-in-place anchor, AND

No seismic load effects

IBC2003 Sec. 1913 (similar IBC2006 Sec. 1912)

References ACI318 App D for Ultimate Strength Design

Addresses some post-installed types


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ACI318 Appendix D (in brief)

Provides a Strength Design Method forAnchor Design

Intended for Anchors:Connecting structural elementsConnecting safety-related attachments tostructural elements

Identifies Possible Anchor Failure Modesand Corresponding Capacities

Requires Post-Installed Anchors be Testedto ACI355.2

Average

Ultimate

Load

(from

Testing)

Estimated

Loads(D,L,W,

E)

Load

Factors

(1.2,1.6,..)

Chara

c-

teristi

c

Capacity

*

Factore

d

Design

Load

(Demand)

Desig

n

Stren

gth

(Capacity)

Address concept of cracked concrete

Huge effect on post-installed anchor market

Testing shows

CIP=25% wedge=40% drop-in=50% adhesives=60%

ACI355.2 Test Standard


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Does NOT address all anchor types, such asAdhesive anchors

Screw anchors

PAT fasteners

Applications NOT covered:

CMU (grout-filled or hollow)

ACI318 Appendix D (in brief)

So What About anchors that are not withinthe scope of Appendix D of ACI318?

What is an approved procedure?

ANCHORAGE TO CONCRETE

STRENGTH DESIGN

1913.1 Scope. The provisions of this section shall govern the strength design of anchors

installed in concrete for purposes of transmitting structural loads from one connected

element to the other. Headed bolt, headed studs and hooked (J- or L-) bolts cast in

concrete and expansion anchors and undercut anchors installed in hardened concrete

shall be designed in accordance with Appendix D of ACI318, provided they are

within the scope of Appendix D.

The strength design of anchors that are not within the scope of Appendix D of

ACI318 shall be in accordance with an approved procedure.


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2003: ICC-ES started creating newer AcceptanceCriteria to provide strength design provisions foranchors not within the scope of Appendix D

2008: ICC-ES removed concrete recognition for

any screw or adhesive anchor NOT tested to thenewer AC s

AC193AC106Conc. Screws

AC308AC58Adhesives

New Criteria(Cracked & uncr. - USD)

Old Criteria(Uncracked - ASD)

Determining anApproved Procedure

So What Anchor Products Can Be Used?


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So What Anchor ProductsCan Be Used?

Building Code (IBC) says what design method to useCIP, expansion and undercut anchors per App DSilent on adhesive & screw anchors

IBC says to use an approved procedure for anchors notwithin the scope of Appendix D

IBC says products with research reports and/or test datacan be considered as alternate materials

Ultimately it is up to the building official

Code requirements are not always known/enforced

Quest ions?


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ACI 318 Appendix D

Anchorage to Concrete

Appendix D

Scope

Failure Modes & Design Equations

Required ACI355.2 Testing

Strength Reduction Factors


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Scope of Appendix D

Strength design method for anchorage toconcrete

(i.e. Nua Nn or Vua Vn)

Cast-In-Place (CIP) anchors

Post-Installed (PI) anchorsUndercut anchors

Torque-controlled expansion anchorsDeformation-controlled expansion anchors

PI anchors must be prequalified per ACI355.2

Scope of Appendix D

Restricted to structural anchors that transmit

structural loads related to

Strength

Stability, and

Life Safety

2 Envisioned Applications:

Connections between structural elements

Safety-related attachments attaching to structuralelements


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7 Possible Failure Modes

Tension (4)

Steel

Concrete Breakout

Pullout/Pull-through

Concrete Side-face Blowout

Shear (3)

SteelConcrete Breakout

Concrete Pryout

Failure Modes

Design Equations

Tension Capacities

Nsa = n Ase,N futaNcb = ANc / ANco ( ec,N ed,N c,N cp,N Nb)

Npn = c,PNpNsb = (160ca1 Abrg) f c

Shear CapacitiesVsa = n 0.6 Ase,V futa

Vcbg = AVc / AVco ( ec,V ed,V c,V h,V Vb)

Vcpg = kcp Ncbg


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Steel Strength in Tension

Steel Strength In Tension D.5.1

Nsa = n Ase,N futa (Eq. D-3)Nsa Nominal tensile strength of ananchor group

n Number of anchors

Ase,N Effective cross sectional area ofanchor in tension

futa Specific ultimate tensile strengthof anchor


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Concrete Breakout Strengthin Tension

Concrete Breakout In Tension D.5.2

Ncb= ANc / ANco ( ec,N ed,N c,N cp,N Nb) (Eq. D-5)

Ncb Concrete breakout strength in tension


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Ncb= ANc / ANco ( ec,N ed,N c,N cp,N Nb)

ANc Projected failure area of group

ANco = 9 hef2 Projected failure area of

one anchor (Eq. D-6)


Ncb=ANc /ANco( ec,N ed,N c,N cp,N Nb)

ec,N: Modification for eccentric load

ed,N: Modification for edge effects

c,N

: Modification for cracking

c,N=1.0 (cracked); 1.4 (uncracked)

cp,N: Modification for post-installed

anchors


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Pullout Strength in Tension

Pullout Strength In Tension D.5.3

Npn = c,P Np (Eq. D-14)

Npn Nominal pullout strength

c,P Modification for cracking

1.0 for cracked

1.4 for uncracked

Np Pullout strength intension


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Pullout Strength In Tension D.5.3

Npn = c,P Np (Eq. D-14)

Np Pullout strength in tension

For PI anchors Np based on ACI

355.2 test results

For CIP anchors, Np based on:Np = 8 Abrgf c (Eq. D-15) headed bolts

Np = 0.9f cehda (Eq. D-16) hooked bolts

Side-Face Blowout Strength

in Tension


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Side-Face Blowout Strength D.5.4

Nsb = (160ca1 Abrg) f c (Eq. D-17)

Nsb Side-face blowout strength (headedanchors only)

ca1 edge distance

Abrg Net bearing area of the head of anchor

Modification factor for lightweight concrete

Steel Strength in Shear


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Steel Strength In Shear D.6.1

Vsa = n Ase,V futa (eq. D-19) CIP HSA

Vsa = n 0.6 Ase,V futa (eq. D-20)

n number of anchors

Ase,V effective cross sectionalarea of a single anchor in shear

futa specified tensile strength of

anchor steel

Steel Strength In Shear D.6.1

Vsa may also be based on theresults of tests performed andevaluated according to ACI 355.2


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Concrete Breakout Strengthin Shear

Concrete Breakout Strength In ShearD.6.2

Vcbg = AVc /AVco( ec,V ed,V c,V h,VVb)(Eq. D-22)

Vcbg Concrete breakout strength inshear


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Vcbg = AVc /AVco( ec,V ed,V c,V h,V Vb)

Vb=7( e /da)0.2 da f c (ca1)

1.5(Eq. D-24)

e load bearing length of anchor

Same as hef if there is no sleeve on anchor

Per manufacturer if there is a sleeve

da outside diameter of anchor

adjustment for lightweight concrete

f c concrete compressive strength

ca1 edge distance


Vcbg = AVc /AVco( ec,V ed,V c,V h,VVb)

AVco maximum projected concrete

failure area of a single anchor

1.5ca1

c a 1

1.5c1

V

1.5ca1

AVco = 4.5 ca12 (Eq. D-23)

AVco


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Vcbg = AVc /AVco( ec,V ed,V c,V h,VVb)

AVc projected concrete failure areaof a group of anchors

AVc = (1.5ca1 + s1 + ca2) ha


ca2s11.5ca1

c a 1

ha

V

AVc

Concrete Breakout In Shear D.6.2

Vcbg = AVc /AVco ( ec,V ed,V c,V h,V Vb )

ec,V Modification for eccentric load

ed,V Modification for edge effects

c,V Modification for crackingh,V Modification for member thickness


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Pryout Strength in Shear

Concrete Pryout Strength In ShearD.6.3

Vcpg = kcpNcbg (Eq. D-30)

kcp = 1.0 for hef < 2.5

kcp = 2.0 for hef > 2.5

Ncbg

Nominal concrete

breakout strength in tension

Always do tension calcs first


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ACI355.2 Testing

ACI355.2 Tests1 . ) Unc racked Conc rete

2 . ) Unc racked & CrackedConcrete3 . ) Unc racked & CrackedConcrete and Se ismic


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Anchoring intoCracked Concrete Regions

Cracking can occur under service loads

Reinforcement controls cracking but does not prevent

cracking

Test to determine how an anchor performs when locatedwhere a crack occurs

Cracked Concrete Tests

Measures reliability in crackswhere the opening width is

cycled

Crack width varies between0.004 and 0.012 inches

1000 Cycles

C.O.V. < 20%Mean residual capacity >0.9Nref

Most difficult to passWiden to = 0.012

Cycle between =0.012 and 0.004


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Seismic Provisions

D.3.3.2 Post-installed structural anchors shall bequalified for use in cracked concrete and shall havepassed the Simulated Seismic Tests in accordancewith ACI 355.2. Pullout strength N p and steelstrength of the anchor in shear V

sa shall be based on

the results of the ACI 355.2 Simulated Seismic Tests.

For Seismic Category C to F, post-installed anchors must be testedto simulated seismic tests

Establishing Anchor Categories

per ACI355.2-01 testing

90#/100# = 0.9

7500#/10000# = 0.75


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Phi ( ) Factors

Phi ( ) factors

Nua Nn or Vua Vn

Phi ( ) factors are applied tonominal capacities beforecomparing with factored forces

Based on:

Supplemental reinforcement

Failure mode

Load type

Anchor Category


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Phi ( ) factors D.4.4

0.700.45Cat. 3

0.700.55Cat. 2

0.700.65Cat. 1

0.700.70

Use Condition B

CIP

Pryout

0.700.45Cat. 3

0.700.55Cat. 2

0.700.65Cat. 1

0.700.70

Use Condition B

CIP

Pullout

0.700.450.750.55Cat. 3

0.700.550.750.65Cat. 2

0.700.650.750.75Cat. 1

0.700.700.750.75CIP

Breakout

0.700.700.750.75CIPSide FaceBlowout

0.600.65Brittle

0.650.75Use Condition B

DuctileSteel

ShearTensionShearTension

Condition BCondition A

Factor

AnchorProperty

Failure Mode

Appendix D Seismic Provisions


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Seismic Provisions

D.3.3 When anchor design includes earthquakeforces for structures assigned to Seismic DesignCategory C, D, E, or F, the additional requirements ofD.3.3.1 through D.3.3.6 shall apply.

D.3.3.2 Post-installed structural anchors shall bequalified for use in cracked concrete and shall havepassed the Simulated Seismic Tests in accordancewith ACI 355.2. Pullout strength N p and steelstrength of the anchor in shear V

sa shall be based on

the results of the ACI 355.2 Simulated Seismic Tests.

Seismic Provisions

D.3.3.3 The anchor design strength associated

with concrete failure modes shall be taken as 0.75 N n and 0.75 V n , where is given in D.4.4 or D.4.5, andN n and V n are determined in accordance with D.5.2,D.5.3, D.5.4, D.6.2, and D.6.3, assuming the concreteis cracked unless it can be demonstrated that theconcrete remains uncracked.

0.75 reduction to concrete capacity in

Seismic Design Category C F


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Seismic Provisions

D.3.3.4 Anchors shall be designed to be

governed by the steel strength of a ductile steelelement as determined in accordance with D.5.1 andD.6.1, unless either D.3.3.5 or D.3.3.6 is satisfied.

D.3.3.5 Instead of D.3.3.4, the attachment thatthe anchor is connecting to the structure shall bedesigned so that the attachment will undergo ductileyielding at a force level corresponding to anchor

forces no greater than the design strength of anchorsspecified in D.3.3.3.

D.3.3.6 As an alternative to D.3.3.4 and D.3.3.5,it shall be permitted to take the design strength of theanchors as 0.4 times the design strength determinedin accordance with D.3.3.3. For the anchors of studbearing walls, it shall be permitted to take the designstrength of the anchors as 0.5 times the designstrength determined in accordance with D.3.3.3.

Seismic Provisions Summary

SummarySeismic Design Category C, D, E & F

PI anchors must pass SimulatedSeismic Test

Design strength reduced by 25%

Ductile steel failure of anchors shallcontrol, or...

Ductile yielding of attachment, or...

Anchor capacity reduced by 60%


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Questions

ICC-ES Acceptance Criteria forAnchors Not Within the Scope of

Appendix D

AC193 for Screw Anchors

AC308 for Adhesive Anchors


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ICC-ES AC193for Screw Anchors

Provides a method to test & evaluate screw anchor productsfor anchoring into concrete

Requires screw anchors to be tested to ACI355.2

Amends ACI318 Appendix D to provide strength designmethod for screw anchors

Manufacturers must provide modified effective embedment depth (hef)

Manufacturers must provide Pullout Capacity (Npn)

Screw Anchor Design Equations per

AC193

Tension Capacities

Nsa = n Ase,N futaNcb = ANc / ANco ( ec,N ed,N c,N cp,N Nb)

Npn = from manufacturer s test data



Vcpg = kcp Ncbg


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Titen HD

USD Tables Tension (p115)

ICC-ES AC308 for Adhesive Products


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ICC-ES AC308for Adhesive Products

Provides test method to evaluate adhesiveproducts used for anchoring into concreteusing anchor theory

adhesive anchors

torque controlled adhesive anchors

Amends Appendix D to:Cover adhesive anchors

Adds concept of bond failure mode for tensionAdds additional pryout check for shear

Cover torque controlled adhesive anchors

AC308 Design RequirementsSummarized on pages 18-19


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Adhesive Anchor Design Equationsper AC308

Tension CapacitiesNsa = n Ase,N futaNcbg = ANc / ANco ( ec,N ed,N c,N cp,N Nb)

Npn = N/A

Nag = Ana / ANaO ( ed,Na g,Na ec,Na p,Na NaO)



Vcpg = min |kcpNag ; kcpNcbg|

Adhesive Strength In Tension AC308

Nag=ANa /ANaO( ed,Na g,Na ec,Na p,Na NaO) (Eq. D-14b)

Adhesive Bond Failure Mode

based on Uniform Bond Stress Method

Takes bond strength of single adhesive anchorthen modifies for:

SpacingEdge

Group effect

Eccentricity

Cracked concrete


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Nag=ANa /ANaO( ed,Na g,Na ec,Na p,Na NaO)

Basic strength of a single adhesive anchorin tension

NaO = k,cr d hef (eq. D-14j)

k,cr bond strength in cracked concrete

d nominal anchor diameter

hef effective embedment depth


NaO = k,cr d hef

k,cr Adhesive bond strength

Dependent on diameter, cracking, temperature


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Nag=ANa /ANaO ( ed,Na g,Na ec,Na p,Na NaO)

ANaO = (scr,Na)2 Projected area of the

failure surface of a single anchor withoutthe influence of proximate edge. (Eq. D-14c)

scr,Na = 20d ( k,uncr /1450) < 3hef (Eq. D-14h)

critical spacing

k,uncr Adhesive bond strength

Ccr

Ccr

Ccr

Ccr

Scr

Ccr

Ccr


Nag = Ana / ANaO ( ed,Na g,Na ec,Na p,Na NaO)

Projected Area Ratio

ANa Projected area of the failure surface for thegroup of anchors that shall be approximated asthe base of the rectilinear geometrical figure thatresults from projecting the failure surfaceoutward a distance ccr,Na from the center lines of

the anchor, or in the case of a group of anchors,from a line through a row of adjacent anchors.

ccr,Na = scr,Na (Eq. D-14i) Critical edge distance

2C

cr

Ccr

Scr


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Nag=Ana / ANaO ( ed,Na g,Na ec,Na p,Na NaO)

Modification Factors:

ed,Na = edge

g,Na = group

ec,Na = eccentricity

p,Na = cracking

Refer to p19 of catalog for more info

Factors for Installation Conditions

Special Inspection

Continuous

Periodic

Concrete Conditions

Dry

Saturated

Modification Factors AC308


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Torque Controlled Adhesive Anchors(TCAA)

Simpson Article inStructure Magazine

May 2008 Issue


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Definition

An adhesive anchor that generatesexpansion forces under tension loading

These forces increase anchor performance

Think of them similar to expansion anchors

Adhesive acts as the clip

ICC-ES AC308 forTorque Controlled Adhesive Anchors

Requires manufactures to perform pullout testsJust like for expansion anchors

Pullout capacity (Npn) determined through testing

Uses same equations of Appendix D


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Torque Controlled Adhesive AnchorDesign Equations

per AC308

Tension CapacitiesNsa = n Ase,N futaNcbg = ANc / ANco ( ec,N ed,N c,N cp,N Nb)

Npn = from manufacturer s test data



Vcpg = kcp Ncbg

Chemical bond

Installation Torque on nut

Frictional bond

SecondaryFrictional bond

P

r e s t r e s s f o r c e s

Why a TCAA works


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IXP with SET-XPTension Design Data (Page 36)

Questions


49/54

Almost Done

Review

Overview of codes pertaining to concrete anchor design &testing

International Building Code (IBC)

ACI318 Appendix D

ACI355.2

ICC-ESAcceptance Criteria

Code Reports

Detailed explanation of anchor design per ACI318Appendix D

Scope, limitations, failure modes & equations

Detailed explanation of possible approved procedure fordesign of anchors not within the scope of Appendix D

ICC-ES AC193 for screw anchors

ICC-ES AC308 for adhesive anchors


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So What Products Does Simpson Have

Tested to Meet the New Requirements?

Simpson Products

Tested to Meet NewRequirements

Page 4


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Simpson ProductsTested to Meet NewRequirements

Strong-Bolt

Expansion Anchor

Titen HD

Concrete Screw Anchor

SET-XP w/ threaded rod and rebar

Adhesive Anchor

SET-XP w/ IXP insert

Torque Controlled Adhesive Anchor

+

+

Strong-Bolt

Expansion Anchor

Tested to ACI318 Appendix D andAC193 requirements

USD Tables in catalog for App Ddesign

Code ReportESR-1771 for concrete


52/54

Titen HD

Concrete & Masonry ScrewAnchor

Tested to AC193 requirements

USD Tables in catalog for App Ddesign

Category 1 anchor

Code Report

ESR-2713 for concreteESR-1056 for masonry

SET XP

Cracked Concrete Adhesive

Specially formulated and tested for AC308requirements

Easy identification

Teal color when mixed

Tested for use with

threaded rodRebar

Special insert (IXP anchor)

Code Report

ESR-2508 for concrete


53/54

IXP Anchor

Torque controlled bonded anchor

For use with SET-XP adhesive

Specially designed & tested to AC308requirements

Expansion behavior in tension zones

Tri-lobular design prevents unscrewing duringtorque or loading

Category 1 anchor

Code Report pending (expected 2009)

Knowing this ..

Will You Start Designing & SpecifyingConcrete Anchors to the LatestStandards?


54/54

Properly Specifying AnchorProducts on Your Projects

Suggested General Note to address qualified anchors onfuture projects

Questions

simpson - crackingtheconcreteanchorcodes

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